Full regeneration of segmental bone defects using porous titanium implants loaded with BMP-2 containing fibrin gels
1 Orthopaedic Research Laboratory, Department of Orthopaedics, Erasmus University, Medical Centre Rotterdam, Rotterdam, The Netherlands
2 Department of Orthopaedics, University Medical Centre Utrecht, Utrecht, The Netherlands
3 Department of Haematology, Erasmus University Medical Centre Rotterdam, Rotterdam, The Netherlands
4 Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
5 Department of Emergency Medicine, Department of Orthopaedics, Erasmus University Medical Centre Rotterdam, Rotterdam, The Netherlands
6 Trauma Research Unit, Department of Surgery, Erasmus University Medical Centre Rotterdam, Rotterdam, The Netherlands
7 Department of Rheumatology, University Medical Centre Utrecht, Utrecht, The Netherlands
8 Department of Orthopaedics Surgery, University Hospital RWTH Aachen, Aachen, Germany
Abstract
Regeneration of load-bearing segmental bone defects is a major challenge in trauma and orthopaedic surgery. The ideal bone graft substitute is a biomaterial that provides immediate mechanical stability, while stimulating bone regeneration to completely bridge defects over a short period. Therefore, selective laser melted porous titanium, designed and fine-tuned to tolerate full load-bearing, was filled with a physiologically concentrated fibrin gel loaded with bone morphogenetic protein-2 (BMP-2). This biomaterial was used to graft critical-sized segmental femoral bone defects in rats. As a control, porous titanium implants were either left empty or filled with a fibrin gels without BMP-2. We evaluated bone regeneration, bone quality and mechanical strength of grafted femora usingin vivoandex vivoµCT scanning, histology, and torsion testing. This biomaterial completely regenerated and bridged the critical-sized bone defects within eight weeks. After twelve weeks, femora were anatomically re-shaped and revealed open medullary cavities. More importantly, new bone was formed throughout the entire porous titanium implants and grafted femora regained more than their innate mechanical stability: torsional strength exceeded twice their original strength. In conclusion, combining porous titanium implants with a physiologically concentrated fibrin gels loaded with BMP-2 improved bone regeneration in load-bearing segmental defects. This material combination now awaits its evaluation in larger animal models to show its suitability for grafting load-bearing defects in trauma and orthopaedic surgery.
Keywords
- BMP
- bone graft
- bone regeneration
- fibrin
- metal surface treatment
- scaffold
- titanium
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